High-temperature radiant-drying system



ITS 63,461

Dec. 1, 1925- J. E. ALEXANDER HIGH TEMPERATURE RADIANT DRYING SYSTEM Filed Npv. 26, 1923 5 Sheets-Sheet l Dec- 1 1925- Y ,563,461

J. E. ALEXANDER HIGH TEMPERATURE; RADIANT DRYING SYSTBII Filed Nov. 26. 1923" a sheets-sheet 2 M, 3 w e a R g R N \n o N w J. E. ALEXANDER HIGH TEMPERATURE RADIANT DRYING SYSTEM Filed N09. 26. 192:

3 Sheets-Sheet 5 Patented Dec. 1, 1925,

JOHN E. ALEXANDER. 0]? PORT EDWARDS. WISCONSIN.

HIGH-TEMPERATURE RADIANT-DRYING SYSTEM.

Application filed November 26, 1923. Serial No. 676.913.

To (/Z/ whom it may concern:

Be it known that I, JOHN E. ALEXANDER, a citizen of the United States, and a resident of the city of Port Edwards, in the county of lVood and State of Visconsin, have invented certain new and in a High-Temperature Radiant-Drying System; and I do hereby declare that the Following is a full. clear,and exact-description of the same, reference being had to the accompanying drawings, and to the numerals of reference marked thereon, which form a part of this specification.

In the conventional types of paper drying uachines at present extensively in use, a great. deal of difliculty and loss is encoun tercd in that the paper sheet fabric, wel. or other material being dried is often burnt or scorched, due to the fact that the fibers on one side'of the web come into direct contact with the heated surfaces of the drying rolls or cylinders, while the fibers on the other side of the web remain moist. It often happens that when higher drying temperatures are used one or both surfaces of the web become encrusted and scared, thereby preventing proper evaporation of the moisture. Vith the arrangement of a series of drying cylinders at present in use the drying machines are enormous in size and require an extremely large amount of floor space as well as being expensive, amount of material required in the construction of the machine. In air circulating systems certain limitations are present in that a given amount of air can only carry away only a given amount of'moisture, regardless of the rapidity with which heat is applied. The excessive weight of the drying cylinders in theprcsent types of machines requires a great driving force applied through extensive gearing which is noisy in operation and requires frequent replacement of parts. It is with a view of overcoming the above men tioned defect in paper drying machines and i to realize. greater economies and efliciencies a comparatively small amount of that the oped.

This invention relates to an improved type of paper drying machine wherein the use of heavy and large drying cylinders or drums and the use of felt belts is eliminated, thereb permitting a machine to be produced whic 1 will occupy floor space,

present invention has been develuset'ul Improvements 'tion to provide a paper on account of the largemore particularly require less material in its construction and less power to operate, thus affording a machine of reduced cost and increased efficiency.

It is an object of this invention to provide a paper drying machine of reduced weight, size and cost, requiring a relatively small amount of driving power without requiring the overcoming of an excessive starting torque.

It is also an objectof the invention to pro ing the web into direct contact with said.

heaters. 1

It is furthermore an object of this invendrying machine wherein the conducted web to be dried is surrounded by a gaseous medium which will consistently dry the web of paper all the way through.

Still another object of the invention is to provide a paper drying machine provided with electric or other types of heaters which are thermostatically controlled and so arranged that theheat can be rapidly applied and concentrated in selected areas to evaporate the moisture from the paper to evenly dry the same.

Another object of the invention is to provide a paper drying machine in which there will be practically no escape of hot gases from the machine since the pressure within the drier is maintained slightly lower than atmospheric by the use of a small exhaust fan on the discharge side of a condenser which will only have to take care of any air which may become entrained in the system, and which will act to draw out the gases so that the escape of said gases into the room containing the machine will be reduced to a minimum.

A further object of the invention is the constructing of a paper drying machine wherein the heat losses from thennit are exceedingly small so that the atmosphere in the room is substantially normal so that it will not be uncomfortable to work in the in room in the-vicinity of the machine.

It is also an object of this invention to provide a paper drying machine wherein the material to be dried isnot brought into contact with-hot metallic surfaces and is not conducted between heated drying rolls and dryergfelts, but is carried on meshed conveyors permitting the heated gaseous medium within the machine to surround and v permeate through the material to uniformly trolled at ditferentlevels and points in the machine for the purpose of removing the moisturefrom thesheet in the quantities de-. sired along the path of travel of the sheet, depending upon the material being dried and the adjustment of the'heater controls.

Other-and further important objects of this invention willbe apparent from the disclosures -in the specification and 'accompanying drawings.

This invention (in a preferred form) is illustrated in the drawings and hereinafter more fully described.

On the drawings: Figure-1 is a side elevation of a paper drying machine with one side removed,v and embodying the principles of this invention.

chine partly tail section taken on line 3-3 of Figure 1.

Figuib 2 is a horizontal; section of,themabroken away and taken on line 2-2 of Figure 1. v

Figure 3 is an enlarged fragmentary de- Figure 4,-isa transverse sectional view taken on'line 4-4 of Figure 2. Y I

Figure 5 is a fragmentary detail section taken on line 5-.-5 of Figure2.

Figure 6 is a detailed sectionwith parts in-elevation illustrating a form of adjustable thermostat used with the drying apparatus of this invention. r

As shown on the drawings:

The machine comprises a casing or housing consistingof .endsections Land 2, and

an intermediate or middle section 3 divided from the end sections by transverse walls "or partitions 4. The walls of the housing end a section 1 and 2 are of double construction having non-conducting air spaces therebetween. Theside walls'of the middle housing section 3 are built up of hollow non-conducting tile 5 or someother suitable heat insulating material.- Doors 6 are provided in the housing end sections 1 and 2,- while the walls} are constructed with doors 7 to. peri'j; interior of the middle cham Y i from an apertured air pressure pipe 20 'receive, a drive from a gear her from the end sections. The walls 4 are. provided with horizontal slots 8 (Figure 5) for a purpose hereinafter described. The

' thereon the gudgeons 12 of an exterior roller 13 around which an endless wire mesh 01' fabric feed conveyor 14 is trained. The feed conveyor 14 passes into the end section 1 through a slot 15 and after passing around an inner roller 16 passes out of the section .t tln'ough a lower slot 17' in the end wall of said section. The upper entrance .slot 15 '15 partially closed by means of a pivoted flap or apron 18. The inner roller 16 has the gudgeons thereof journalledin bearings formed on the top of a second pair of pedestals or supports 19 mounted upon the floor within the entrance end section 1 of the machine housing. A'wet paper or fabric web to be dried is fed onto the upper span of the feed conveyor 14, and is thus conveyedinto the housing end section 1 through the slot 15 and is loosened or separated from said feed conveyor by means of currents of air blown One of the gudgeons 21-of the inner roller 16' projects through its supporting bearing and has a gear 22 fixedon the end thereof in mesh with a gear 23 mounted on a driving shaft 24. .The driving shaft 24 projects out "of the housing end section 1 and is connected with any suitable source of driving power,

such as a motor-or the like.

The shaft .24 is journalled in bearings mounted on the lower cross bars 25 secured to frame uprights 26 rigidly mounted within the housing section 1. A roller 27 is engaged on'the shaft 24 on'a level with the' rollers 13 and 16s A plurality of pairs of. cross bars 25 aresecured to the uprights 26v ,at difierent levels and support the shafts 28 of a plurality of rollers 29. Fixed on one end of each of the roller shafts 28 is a gear 30. The gears 30 'mesh with one another and 31 on the lower shaft 24.

.A pair of frames or racks are alsomounted in the outlet end section 2 with each of said 1, frames comprising uprights 26 and cross bars 25. A plurality of shafts 32 are rotatably supported on the cross bars 25 and have rollers33- mounted thereon at levels corresponding to the level' of the rollers 29 and 27 respectively.

- Rigidly mounted within the intermediate i housing section 3 are a plurality of upright vertical members 34, to which a plurality of horizontal members 35 are secured. Journalled on the frames within the intermediate housing section 3 are a plurality of vertical transverse rows of guide rolls 36. The guide rolls 36 are arranged to lie in different horizontal planes so that the upper level of each set of the rolls in each horizontal plane is positioned above the upper level of the respective sets of end rollers. 29 and 33 and the lower set of the end rollers 27 and 33. The lower set of rolls 36 are positioned with the upper level thereof in the plane of the lower level of the roller 27 and the lowermost roller 33. The remaining sets of rolls 36 are positioned with the upper levels thereof slightly above the lower levels of the respective sets of end rollers 29 and 33.

Engaged around each horizontal set of end rollers 29 and 33 and around the lower set of rollers 27 and 33, is an endless wire mesh or fabric belt or conveyor 37. The lower lap of the lowermost belt 37 runs over the lowermost set of guide rolls 36, and when leaving the roller 27 passes upwardly in an inclined plane to pass over the second set of guide rolls 36 and then downwardly in an inclined plane back around the lowermost roller 33. The wire mesh or fabric belts 37 from each of the rollers 29 pass upwardly to the planes of the respective guide rolls 36 as clearly illustrated in Figure 5. -This arrangement of the belts over the end rollers and the intermediate guide rolls serves to hold the belts properly tensioned. To fur ther afford a means oftensioning the belts 37 the rollers 33 are supported on slidable supports having depending counter weights 38 connected therewith by cables which run over suitable idler pulleys 38 (Fig. 2) and which act to pull the rollers 33 outwardly, thereby tensioning the belts.

The belts 37 are'provided at different elevations for the purpose of conducting a paper or fabric web upwardly in a circuitous path through the end chambers and through the intermediate heated chamber of the machine housing, and out through the upper end of the end housing section 2. If desired, the paper or fabric web may enter the top section of dryer and may be con ducted downwardly in a circuitous path,

passing out of the lower portion of the housing.

The intermediate housing section 3 is electrically heated by means of a plurality of horizontal layers of electric heating units 39 which are supported transversely in the section 3 by the' horizontal members 35 (Figure 3') and are adapted to produce relatively 'high temperatures. With this arrangement one horizontal set of electric heating units 39 is positioned between the upper and low-' therewith. The electric units 39 are connected with any suitable source of electrical energy with the electric units at each level connected with adjustable thermostats 40 at each end of the intermediate housing section 3. so that the heating units at each level may be automatically controlled by the thermostats whereby different relatively higher temperatures may be maintained at temperatures are exceeded. This operation is, of course, controllable by the positionof the screw contacts 40. It will, of course, be understood that any commercial form of adjustable thermostats might be used in lieu of those shown and described herein.

The operation is'as follows:

A material to be dried such as a wet paper or fabric web' is delivered to the wire mesh or fabric feed belt 14, and is conveyed into the drying machine through the inlet slot 15 when the machine in operation driven from the shaft 24. The rollers 13 and 16v receiving their drive through the meshing gears 22 and 23. The various rollers 27 and 29 are rotated from the drive gear 31 andthe meshing gears 30, thereby causing the wire mesh or fabric belts 37 to rotate and passover the guide rolls 36 and the respective rollers 33.

.move away from said contacts when such The wet web delivered tothe belt 14 is I conveyed into the end housing section 1 through the slot 15., and as the web starts to pass around the roller 16 the air blasts from the air pipe 20 (Figure 5). blowing under the web, act to separate the web from the belt 14 and permits the loosened web to be conducted over onto the inclined portion of the 11 per lap of the lowermost wire mesh belt 3 and then between said upper la belt immediately thereabove. The wet web 'isthus conveyed between two wire mesh or fabric belts through one of the openings 8 into the intermediate heated chamber of the housing section 3, then out into the end section 2 and back into section 3 upwardly in a circuitous path below and above the various sets of electrical heating-units 39 and finally out ofthe upper end of the end section 2. If desired, the path of travel of of the lowermost belt and the lower lap o the er laps of each belt 37 and out of contact the material to be dried maybereversed. 139

results.

:vapor such as superheated steam emanating from the material which is being dried and since there are no air inlets of any substantial area leading into the casing, air is excluded therefrom by the pressure of the heated gaseous medium or steam' and there is no air in the chamber during the drying operation. The web, when being dried by the heat from the heating units, cannot be burned or scorched, inasmuch as the ,temperature of the wet web in the section 3 cannot rise above 212 at atmospheric pressure. As soon as any particles of moisture in the Web reaches a temperature higher than 212 it IS turned into steam and removed through the hood 9 and the exhaust pipe 10. (Figure 4.)

The paper web is thus uniformly dried without the use of air as a circulating medium and without any danger of being burnt, seared or scorched. Since air is not used as a circulating medium, the rapidity with which the moisture can be evaporated from the web is practically unlimited and depends primarily upon the rapidity with which the heat can be applied and concentrated. The heat is applied by the electric or any other suitable heating units, which are governed by the respective thermostats which may be set so thatthegreatest heat may be applied to the portions of the web containing the most moisture. The setting of the thermostats permits diiferent temperatures to be maintained in different locations within the machine housing, so that the temperature ap lied at the drier portions of the web nee not be as great as the temperatures applied at the Wet portions of the web at the entrance end of the heated drying chamber. The heating and drying of the Web can bereadilv controlled automatically in different sections of the machine, and the tern erature gradient can be arranged to pro uce the most efficient and economical In View of the fact that the pressure with in the housing is somewhat below atmospheric and the amount of air entering the drier is relatively small compared to the total gases handled, there will be no hot gases escaping from the heater itself since whatever gas movement there may be will be from the outside toward the interior of the drier. Employees. working around the drier willnot be subjected to 'iniurv from the escaping gases and from the intense heat which ordinarily surrounds driers.

I am aware that numerous details of construction may be varied through a wide passage through the housing, and means con-- nected with said -heating units for. auto-.

matically controlling the same to regulate thetemperatures in different parts'of the housing.

2. In a machine for drying paper or simi lar material, a substantially closed chamber from which incoming air is excluded during the dryin operation, means for conveying thematerial to be 'driedthrou'gh said chamber and high temperature heating elements in the chamber for maintaining the temperature therein substantially at or in excess of the vaporizing'tempe'rature of water so as to first vaporize the water in the paper or similar materials andthen to heat the water or other substance so vaporized and maintain it at or above its vaporizing temperature during the drying operation until it is discharged or withdrawn from the chamber.

3. In a machine for drying paper or similar material, a substantially closed chamber from which incoming air is excluded during the drying operation, means for conveying the material to be dried through said chamber and high tem erature heating elements in the chamber or maintaining the temperature therein in excess of the vaporizing temperature of water so as to first vaporize the waterin the paper or similar materials and then to heat the water or other sub stance so vaiporized and maintain it above its vaporizing temperature. during the drying operation until it is discharged or withdrawn from the chamber.

4. In a drying machine the combination with a housing, of heating units therein,'and means for automatically controlling said units for the purposev of obtaining gradient temperatures in said housing.

-5. In a drying machine the combination with a drying housing, of heating units therein, and adjustable thermostatic mechanisms in different parts of the housing connected with the various heating units for obtaining gradient temperatures in said housing. e

6. A drying machine comprising a housing the housing into an intermediate section' and end sections, conveyors extending from the end sections through sald Intermediate sections, heaters in said intermediate section, and adjustable thermostatic means in said intermediate section for automatically governing said heaters.

7. A drying machine comprising a housing, slotted walls in said housing dividing the same into end sections and an intermediate section. doors in the housing to afford access to said end sections, doors in said walls to afford access from the end sections to said intermediate section. conveyors in the housing operating through said slotted walls for conducting a material to be dried through the end sections and through the intermediatesection, heating units in said intermediate unit, and thermostatic mechanisms connected with said heating units for automatically governing the same.

8. A drying machine comprising an insulated housing, slotted partitions therein dividing the housing into end sections and an intermediate section, and foraminous conveyors in said housing traveling through said slotted walls for conducting a material to be dried alternately through the end sections and said intermediate section.

9. A drying machine comprisin sulated housing, slotted walls therein-1 dividing the housing into end sections and an intermediate section, foraminous conveyors in said housing operating in said end sections and through said intermediate section, heaters in said intermediate section, auto: matic controls for said heaters, and a gas and vapor relief and exhaust connected with the intermediate section.

10. A drying machine comprising a. housan in ing divided into end sections and an inter- -mediate section, a gas and vapor relief connected with the intermediate section for maintaining the. pressure within the housing slightly below atmospheric pressure, heaters in said intermediate sections, conveyors in said housing operating through the intermediate section to conduct a material to be dried between said heaters, and controls for said heaters at different levels in said intermediate section for automatically obtaining gradient temperatures within said intermediate section.

11. The method of drying paper or similar material comprising subjecting the same in a chamber from which air is substantially excluded to the drying action of superheated vapor emanating from the material itself.

12.The method of drying paper or simi-.

-lar material comprising conveying the material through a substantially closed chamher from which a circulation of incoming air is substantially excluded during the drying operation and maintaining the temperature in said casing in excess of the vaporizing temperature of water so as to first vaporize the water in the paper or similar materials to be dried and to heat the water or other substance so vaporized and maintain it at or above its vaporizing temperature during the drying operation until it is discharged or withdrawn from the chamber.

13. The method of drying a material by conductin the same through a circuitous path in a ousing, wherein air is not a cir culating medium and wherein graduated temperatures are automatically maintained.

. In testimony whereof I have hereunto subscribed my name.

\ JomIE. ALEXANDER- I 

